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STOCKHOLDERS' EQUITY (Details 10) (USD $) | 12 Months Ended
--- | ---
Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011
401(k) Plan |  |  |
Matching contribution by employer (as a percent) | 75.00% | 100.00% | 100.00%
Period of vesting of matching contributions | 4 years | 4 years | 4 years
Service period of employees | 4 years | 4 years | 4 years
Unvested amount under the defined-contribution savings plan to be amortized | $ 369,000 |  |
Geron 401K Plan |  |  |
401(k) Plan |  |  |
Operating expenses as a result of accelerated vesting of unvested prior employer matches for employees affected by recent restructurings | 266,000 | 370,000 |
Research and development | Geron 401K Plan |  |  |
401(k) Plan |  |  |
Operating expense recorded for vested portion of employer matching contribution | 156,000 | 616,000 | 1,179,000
General and administrative | Geron 401K Plan |  |  |
401(k) Plan |  |  |
Operating expense recorded for vested portion of employer matching contribution | $ 157,000 | $ 259,000 | $ 288,000

X
- Definition Represents the accelerated vesting amount in unvested prior employer matches for employees affected by restructuring under the defined contribution plan. + References No definition available. + Details
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- Definition Represents the period of service of an employee must complete to be fully vested in an employer matching contribution. + References No definition available. + Details
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- Definition Represents the unvested amount of employer matching contributions to be amortized under the defined-contribution savings plan as the corresponding years of service are completed by the employees. + References No definition available. + Details
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- Definition Represents the period over which matching contributions invested in common stock will vest ratably for each year of service completed by the employee. + References No definition available. + Details
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- Details
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- Definition The amount of the cost recognized during the period for defined contribution plans. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6414718&loc=d3e28014-114942 + Details
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- Definition Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan. + References No definition available. + Details
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